Cindy Strnad on sun 7 oct 01
Dear Susan,
Now-a-days, we usually make our numbers add up to
100, but these recipes will work just as easily.
The black copper oxide, for example, is 2.5 parts.
Whatever you'd like to designate as your "part",
be it pound, ounce, gram, kilogram--whatever
weight unit you feel comfortable with will be
fine. If your weight unit is the gram, you'll end
up with 77.5 grams of dry glaze for your Basic
Bronze recipe. Or you can increase them all,
proportionately, to force the recipes to add up to
100. But really, they're fine as they are,
especially for testing purposes.
Best wishes,
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com
SusanRaku@AOL.COM on sun 7 oct 01
The following are recipes that were listed by Marianne Bornet in April. I
would appreciate an explanation of what these mean as I am used to formulas
that add up to 100.
Basic Bronze
Black Copper Oxide 2.5
manganese Dioxide 48
China Clay (EPK) 15
Ball Clay 12
Colin Pearson Bronze
Manganese dioxide 10
Copper Oxide 1
China Clay 1
Glaze Binder 1
Marianne Bornet on mon 8 oct 01
Hi Susan
When I tested these glazes, I weighed them as parts - in my case in grammes.
I hope that this clarifies the equations as its easier than converting them
into percentages.
Regards
Marianne
SusanRaku@AOL.COM on mon 8 oct 01
Hi Cindy. Thank you for your help. When a recipe is by parts, does that
always mean weight or can it mean volumn? These would be very different.
Sussan
Cindy Strnad on mon 8 oct 01
Hi, Susan.
Unless the recipe specifies volume, it should be
parts by weight. Volumetric measuring isn't very
accurate, and most of us don't use it.
Best wishes,
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com
chris clarke on tue 9 oct 01
these formulas look strange to me also but I can tell you that my formulas
do not add up to a hundred. I eliminate decimals totally so they hardly
ever add up. chris
temecula, california
chris@ccpots.com
www.ccpots.com
----- Original Message -----
From:
To:
Sent: Sunday, October 07, 2001 3:34 PM
Subject: need help with formulas
> The following are recipes that were listed by Marianne Bornet in April. I
> would appreciate an explanation of what these mean as I am used to
formulas
> that add up to 100.
>
>
>
> Basic Bronze
> Black Copper Oxide 2.5
> manganese Dioxide 48
> China Clay (EPK) 15
> Ball Clay 12
>
> Colin Pearson Bronze
> Manganese dioxide 10
> Copper Oxide 1
> China Clay 1
> Glaze Binder 1
>
>
____________________________________________________________________________
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>
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melpots@pclink.com.
John Baymore on tue 9 oct 01
Volumetric measuring isn't very accurate, and most of us don't use it.
Cindy,
Oh so very well said.
Volumetric measure is highly variable as to exactly HOW the scooping out
action is performed. Weigh out 200 grams of materials on a triple beam a=
nd
the accuracy is plus or minus about point one grams (1/10 of a gram). A
very small percentage margin of error. Scoop out a volumetric cups worth=
of material, and the plus and minus accuracy figure is WAY different. =
Multiple grams different on a cup volume.
If you are looking at any kind of accuracy....... weigh your materials. =
If
you like surprises or are doing something that has WIDE latitude for
variation.......... than volumetric might be your cup of tea. Neigh on t=
o
useless for really serious glaze chemistry work and real understanding at=
the technical level. =
Volumetric works OK in the kitchen...... but even in that application not=
all the time. =
The CONCEPT is fun to play with....... AFTER you really own the technical=
understanding of raw materials and glaze chemistry..... and then can let =
go
of all that and work intuitively. But even then....stay away from really=
toxic materials.
BTW......... Liquid volumetric testing with the specific gravities matche=
d
is a different animal than weighing dry powders. In that case, you can
work with a known accurate amount of dry materials suspended in the liqui=
d.
Best,
..............................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JohnBaymore.com
JBaymore@compuserve.com
John.Baymore@GSD-CO.com
"Earth, Water, and Fire Noborigama Woodfiring Workshop 2002 Dates TBA"=
Ron Roy on thu 11 oct 01
Beware the dust and fumes of Manganese - inform yourselves of the problems
of Manganese exposure.
RR
>The following are recipes that were listed by Marianne Bornet in April. I
>would appreciate an explanation of what these mean as I am used to formulas
>that add up to 100.
>
>
>
>Basic Bronze
>Black Copper Oxide 2.5
>manganese Dioxide 48
>China Clay (EPK) 15
>Ball Clay 12
>
>Colin Pearson Bronze
>Manganese dioxide 10
>Copper Oxide 1
>China Clay 1
>Glaze Binder 1
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
Wade Blocker on thu 11 oct 01
Ron,
To get 100% you add up all the numbers given, then divide each number by
that total and multiply by 100. that will give you the percentage.
eg. Black Cu ox 2.5
Mang dioxide 48.00
EPK 15.00
Ball clay 12.00
Total 77.5
therefore 2.5 divided by: 77.5 = 0.032258 x100=3.22%
48.00 divided by 77.5 = 06193548 x100 =61.94%
15.00 divided by 77.5 = 0.1935483 x100=19.35%
12.00 divided by 77.5 = 0.1548387 x 100 =15.48%
Total 99.99%
If I carried the decimal points further than undoubtedly I would reach
the correct number of 100.
I apologize calling you by your surname. The minute I hit the send
button I realized my mistake. Mia in ABQ
miriam shelomith on thu 11 oct 01
The other way to look at this is: 77.5, be they grams, pounds, pineapples or pots, is 100%. If the listed items, in the amounts listed, are put in a container, when you are finished adding the last of the items on the list, you will have added 100%.
Surely, it is easier to work with whole numbers, except for the one addition @ 2.5, than the % that can go on forever.
pottermim who shall have for dinner a 100% home grown pineapple picked from the backyard
>Ron,
> To get 100% you add up all the numbers given, then divide each number by
>that total and multiply by 100. that will give you the percentage.
> eg. Black Cu ox 2.5
> Mang dioxide 48.00
> EPK 15.00
> Ball clay 12.00
>
> Total 77.5
>
> therefore 2.5 divided by: 77.5 = 0.032258 x100=3.22%
> 48.00 divided by 77.5 = 06193548 x100 =61.94%
> 15.00 divided by 77.5 = 0.1935483 x100=19.35%
> 12.00 divided by 77.5 = 0.1548387 x 100 =15.48%
>
>
> Total 99.99%
>
>
>
> If I carried the decimal points further than undoubtedly I would reach
>the correct number of 100.
> I apologize calling you by your surname. The minute I hit the send
>button I realized my mistake. Mia in ABQ
>
>______________________________________________________________________________
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